Improvement in purifying and amalgamating gold and silver bearing sands



BENJAMIN F. PENNIMAN, OF SAN FRANCISCO, CALIFORNIA.

I IMPROVEMENT IN PURlFYlNG AND AMALGAMATlNG GOLD AND SlLVER BEARING SANDS. &c.

Specifica i n forming part of Letters Patent No. 180,058, dated July 18, 1876 application filed February 23. 1876.

To all whom it may concern:

Be it known that I, BENJAMIN F. PENNI- MAN, of the city and county of San Francisco, State of California, have invented a new. and useful process for the purifying and amalgamating with quicksilver the aurit'erous or argentit'erous sand, grave], or earth found -on the shores of the sea, and other portions of the United States of America, containing the precious metals gold, silver, 860.; and I do declare that the following is a full, clear, and exact description of the same- The object of my invention being to neutralize and destroy the sulphur and all other impurities found in the sand, gravel, 850., above-mentioned, by the use of certain chemicals, hereafter named, mixed with the sand, gravel, 850., and quicksilver and water, that are to be treated, and then subjecting the same to the action of steam, superheated or not, or to a direct fire-heat. By this means the sand, gravel, 8m, may be freed from their impurities, so that their precious metals, gold, silver, 850., can be the'more readily and properly amalgamated with quicksilver. In this manner sand, gravel, &c., containing sulphur and other impurities, may be made to yield up their precious metals, by being more easily and perfectly amalgamated with quicksilver than by the present ordinary methods of gathering the precious metals from the sand, gravel, 850., in which the action of quicksilver or.

mercury is, to a very great extent, )rejudiced by the presence of the impurities found in the sand, gravel, 820.

To enable others skilled in the art to which ,it appertains to compound and use my process, I will proceed to describe in detail the manner and process of its composition and operation.

The auriferous or argentiferous sand, grav-' pan or pans by the use otmullers, and the quicksilver for amalgamating is then applied, the heat being raised to 2000, varying, if necessary, according to thenature of the sand,

pose to use in treating aurit'erous or argontiferous sands, 860., would be, for one ton of either, four (4) pounds of caustic soda, three (3) pounds of nitrate of soda, two (2) pounds of soda-ash, and two (2) pounds of borax, but these proportions may be varied to suit the exigencies of the case; and to avoid waste, and to obtain the best results in the most economical manner, it may be advisable, before operating upon a large quantity of sand, 850., to begin with a few experiments, for the purpose of determining, with exactitude, the proportions of, the chemicals required.

In a similar manner it may be found convenientand advantageous in some cases to replace the nitrate of soda with saltpeter; and under circumstances when all the chemicals cannot be obtaincd, and a partial effect would still be desirable, the use of some of them only, involving, however, the use of atleast one of an acid and one of an alkaline nature, in combin-ation with the steam or other heat, in the manner described, may be adopted; but I prefer the chemicals and their proportions, or their equivalents, which I have herein n-fentioned.

The process for cleansing the auriferous or argentit'erous sands, gravel, 8m, so that the precious metals they contain can be more readily amalgamated with quicksilver, being continuous, its operation is subj'ectonly to the good judgment of those who may use my process as described; thesame may be said respecting the quantityof quicksilver or merenry to he nsed in :unalgamating', in accordance with the richness of the sand, &c., to be treated.

I claim as my invention- The herein-described process for treating and unialgnmatiug anril'eronsor argentiferous sands, gravel, earth, 850., which consists in mixing them with caustic soda, soda-ash, ni-

I t-mtesoda, and bomx, substantially in the manner and proportions specified, and. then i amnlgamating' in the usual way, substantially l as herein set forth.

I BENJAMIN F. PENNIMAN. Witnesses i I JOHN HAMILL,

l B. .T. SHAY. 

